Solid-state imaging device

Abstract

A solid-state imaging device according to the present disclosure includes: a charge storage region that stores a signal charge obtained through photoelectric conversion in a photoelectric conversion film; an amplification transistor that amplifies the signal charge stored in the charge storage region in a corresponding pixel; a contact plug that is electrically connected to the charge storage region and contains a semiconductor material; and a line that is disposed above the contact plug and contains a semiconductor material. The contact plug and the charge storage region are electrically connected, and the contact plug and a gate electrode of the amplification transistor are electrically connected via the line.

The invention claimed is: 
     
       1. A solid-state imaging device comprising:
 a semiconductor substrate; 
 a plurality of pixels that is disposed in a matrix above the semiconductor substrate; 
 a pixel electrode that is disposed in each of the pixels and electrically isolated from an adjacent one of the pixels; 
 a photoelectric conversion film that is disposed above the pixel electrode and performs photoelectric conversion of light into a signal charge; 
 a charge storage region that is disposed in each of the pixels, is electrically connected to the pixel electrode, and stores the signal charge obtained through the photoelectric conversion in the photoelectric conversion film; 
 an amplification transistor that is disposed in each of the pixels and amplifies the signal charge stored in the charge storage region in a corresponding one of the pixels; 
 a first contact plug that comprises a semiconductor material having semiconducting properties; 
 a line that is disposed above the first contact plug and the charge storage region and comprises a semiconductor material having semiconducting properties; and 
 an element isolation region that is adjacent to the charge storage region, 
 wherein the first contact plug and the charge storage region are electrically connected, 
 the first contact plug and a gate electrode of the amplification transistor are electrically connected via the line, 
 the line is disposed so as to cover at least a portion of the charge storage region in a plan view of the solid-state imaging device, 
 the charge storage region includes an impurity diffusion layer in direct contact with the first contact plug, and 
 the line is disposed so as to cover a portion of the element isolation region in the plan view of the solid-state imaging device, 
 wherein a height of a connection surface between the line and the first contact plug from an upper surface of the semiconductor substrate is less than a height of an upper surface of the gate electrode of the amplification transistor from the upper surface of the semiconductor substrate. 
 
     
     
       2. The solid-state imaging device according to  claim 1 , further comprising:
 a gate electrode of a reset transistor that resets the charge storage region; and 
 a sidewall layer that covers a lateral surface of the gate electrode of the reset transistor, 
 wherein the sidewall layer is disposed without overlapping the first contact plug in the plan view of the solid-state imaging device. 
 
     
     
       3. The solid-state imaging device according to  claim 1 , further comprising
 a second contact plug that is electrically connected to the line on an upper surface of the line, 
 wherein the second contact plug is disposed so as to avoid a portion directly above the first contact plug in a sectional view of the solid-state imaging device. 
 
     
     
       4. The solid-state imaging device according to  claim 1 ,
 wherein the height of the connection surface between the line and the first contact plug from the upper surface of the semiconductor substrate is greater than a height of a bottom surface of the gate electrode of the amplification transistor from the upper surface of the semiconductor substrate. 
 
     
     
       5. The solid-state imaging device according to  claim 3 ,
 wherein the second contact plug comprises a metallic material. 
 
     
     
       6. The solid-state imaging device according to  claim 2 ,
 wherein a gate oxide film for the amplification transistor and a gate oxide film for the reset transistor have a same thickness. 
 
     
     
       7. The solid-state imaging device according to  claim 1 ,
 wherein the charge storage region is an n − -type charge storage region. 
 
     
     
       8. A solid-state imaging device comprising:
 a semiconductor substrate; 
 a plurality of pixels that is disposed in a matrix above the semiconductor substrate; 
 a pixel electrode that is disposed in each of the pixels and electrically isolated from an adjacent one of the pixels; 
 a photoelectric conversion film that is disposed above the pixel electrode and performs photoelectric conversion of light into a signal charge; 
 a charge storage region that is disposed in each of the pixels, is electrically connected to the pixel electrode, and stores the signal charge obtained through the photoelectric conversion in the photoelectric conversion film; 
 an amplification transistor that is disposed in each of the pixels and amplifies the signal charge stored in the charge storage region in a corresponding one of the pixels; 
 a first contact plug that comprises a semiconductor material having semiconducting properties; and 
 a line that is disposed above the first contact plug and the charge storage region and comprises a semiconductor material having semiconducting properties, 
 wherein the first contact plug and the charge storage region are electrically connected, 
 the first contact plug and a gate electrode of the amplification transistor are electrically connected via the line, 
 the line is disposed so as to cover at least a portion of the charge storage region in a plan view of the solid-state imaging device, 
 the charge storage region includes an impurity diffusion layer in direct contact with the first contact plug, and 
 the first contact plug and the line comprise polysilicon, 
 the first contact plug and the line are of a same conductivity type, and 
 the polysilicon has an impurity concentration ranging from 10 19 /cm 3  to 10 21 /cm 3 , 
 wherein a height of a connection surface between the line and the first contact plug from an upper surface of the semiconductor substrate is less than a height of an upper surface of the gate electrode of the amplification transistor from the upper surface of the semiconductor substrate. 
 
     
     
       9. The solid-state imaging device according to  claim 8 ,
 wherein the charge storage region and the first contact plug are of a same conductivity type, and 
 the first contact plug has an impurity concentration higher than an impurity concentration of the charge storage region. 
 
     
     
       10. The solid-state imaging device according to  claim 9 ,
 wherein the impurity concentration of the charge storage region ranges from 10 16 /cm 3  to 10 18 /cm 3 . 
 
     
     
       11. A solid-state imaging device comprising:
 a semiconductor substrate; 
 a plurality of pixels that is disposed in a matrix above the semiconductor substrate; 
 a pixel electrode that is disposed in each of the pixels and electrically isolated from an adjacent one of the pixels; 
 a photoelectric conversion film that is disposed above the pixel electrode and performs photoelectric conversion of light into a signal charge; 
 a charge storage region that is disposed in each of the pixels, is electrically connected to the pixel electrode, and stores the signal charge obtained through the photoelectric conversion in the photoelectric conversion film; 
 an amplification transistor that is disposed in each of the pixels and amplifies the signal charge stored in the charge storage region in a corresponding one of the pixels; 
 a first contact plug that comprises a semiconductor material having semiconducting properties; and 
 a line that is disposed above the first contact plug and the charge storage region and comprises a semiconductor material having semiconducting properties, 
 wherein the first contact plug and the charge storage region are electrically connected, 
 the first contact plug and a gate electrode of the amplification transistor are electrically connected via the line, 
 the line is disposed so as to cover at least a portion of the charge storage region in a plan view of the solid-state imaging device, 
 the charge storage region includes an impurity diffusion layer in direct contact with the first contact plug, 
 the charge storage region and the first contact plug are of a first conductivity type, 
 the solid-state imaging device further comprises a second conductivity type semiconductor layer that is disposed so as to contact an upper portion of the charge storage region, and 
 the second conductivity type semiconductor layer is disposed so as to surround the first contact plug in the plan view of the solid-state imaging device; 
 wherein a height of a connection surface between the line and the first contact plug from an upper surface of the semiconductor substrate is less than a height of an upper surface of the gate electrode of the amplification transistor from the upper surface of the semiconductor substrate.